<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <table border="1">
        <tr>
            <td>id</td>
            <td>Name</td>
            <td>age</td>
            <td>sex</td>
        </tr>
        {% if cats_list %}
            {% for cat in cats_list %}
                <tr>
                    <td>{{ cat.name }}</td>
                    <td>{{ cat.age }}</td>
                    <td>{{ cat.sex }}</td>
                </tr>
            {% endfor %}
        {% elif %}
    </table>
</body>
</html>